Is there a way to get smaller XML report just with host, nvt and ports tree path information?
No not really. You could actually write a report format that reduces the XML report.
Some background information. Our report formats are mostly XSLT files that transform the report response from our API into some other format. The XML report format is just 1:1 the content of the report response.
As a side note for further new threads: Initially the “Vulnerability Tests” category was chosen, this category should be only used for discussing e.g. the results of VTs / NASL files as outlined in the category description. Other questions like this are completely outside of the category scope.